I. Field
The present disclosure relates generally to electronics, and more specifically to biasing circuits for amplifiers.
II. Background
Amplifiers are commonly used in various electronic devices to provide signal amplification. Different types of amplifiers are available for different uses. For example, a wireless communication device such as a cellular phone may include a transmitter and a receiver for bi-directional communication. The transmitter may include a driver amplifier (DA) and a power amplifier (PA), the receiver may include a low noise amplifier (LNA), and the transmitter and receiver may include variable gain amplifiers (VGAs).
An amplifier may be designed to operate with a target bias current, which may be selected based on the desired performance of the amplifier. The target bias current may be obtained by applying a suitable bias voltage to the amplifier. This bias voltage may be fixed and may then result in a bias current that may vary with aging of the amplifier, temperature, and other phenomena. The bias current may thus deviate from the target bias current, and the deviation may adversely impact the performance of the amplifier. For example, a lower or higher bias current may cause the output power of the amplifier to shift, which may be undesirable.